"extraKey" property on React component erases CodeMirror default key map behavior

Current Behavior

When a user defines the extraKey property on the <ReactSimpleMDE /> component, it overwrites/erases the default key handler behavior for the entire component such that the editor stops reacting to events like Cmd-P (Preview) and F11 (Full screen editor), among others.

Questions

1. Is this intended behavior? It seems from the CodeMirror documentation the extraKeys property is meant to add keymaps in addition to the default keymap. See documentation here:

   Can be used to specify extra key bindings for the editor, alongside the ones defined by keyMap.

2. (Assuming the answer to #1 is “no”) Is this behavior that react-simplemde-editor is causing, or is it a downstream dependency (i.e. - CodeMirror or SimpleMDE)?

Workaround

Set the SimpleMDE getInstance to capture the ref, then add your own keymap on top of what the default codemirror behavior is:

// Handler
getInstance = (simplemde) => {
  simplemde.codemirror.addKeyMap({
    Up: (cm) => {
      cm.replaceSelection(" surprise. ");
    },
    Down: (cm) => {
      cm.replaceSelection(" surprise again! ");
    }
  });
}

// JSX
<SimpleMDE
  getMdeInstance={getInstance}
  {...otherProps}
/>

CodeMirror Repro

Here is the problem in action (also viewable here): https://codesandbox.io/s/compassionate-fire-db63m

And here is the problem fixed by my workaround: https://codesandbox.io/s/dark-mountain-51kuy

Here is a screenshot of the problematic behavior in the online sample referenced in the README

[RIP21]

I really need to spent few hours one day addressing those… Sorry, I’m building a startup as a CTO and Co-founder (basically doing all the shit in the world) now and I barely have time for myself let alone some library that I don’t use for last 3 years 😃 So, I cannot promise, but I’ll try do smth today (will be fun to read this 3 years after while this issue will be still open 😄) But I’ll try folks, I’ll try to. Maybe it’s time to rewrite it using hooks? Will see.

[RIP21]

4.1.4 has this fixed. Just published.